The invention relates to marine propulsion systems having an exhaust elbow extending from the engine and discharging engine coolant water into the engine combustion product exhaust.
Exhaust elbows for marine propulsion systems are known, for example as shown in U.S. Pat. Nos. 3,541,786 and 4,573,318, incorporated herein by reference. The elbow extends from the engine manifold and has separate intake passages for exhaust and water. The elbow discharges mixed exhaust and water.
Wate ingestion is a significant problem in exhaust elbows for marine propulsion systems. Engine pulsations due to reciprocating piston movement tends to suck any water within or at the outer tip of the elbow back into the engine, which is undesirable. Water can tend to collect at the discharge end tip of the elbow where coolant water is discharged into the exhaust to mix therewith. Water or moisture deposited or formed at this outer tip end actually travels backwards into the interior of the exhaust passage within the elbow in a pulsating manner and eventually back into the engine. This pulsating ingestion becomes more pronounced with increasing engine size.
The present invention addresses and solves the above noted problems, and provides further improvements beyond those shown in above incorporated U.S. Pat. No. 4,573,318. The present invention provides a trough member which extends the length of the water travel channel along the exhaust elbow and provides a clean sharp parting surface for the water.